This request was easy for Lupangster, who uses only one email account, his gmail account. He received all mails, including all Facebook updates from this gmail account. Why was Facebook team info+rzcifs@support.facebook.com asking him the obvious that it should know? Nevertheless,
after stating the above to info+rzcifs@support.facebook.com, he got the following reply:

When Lupangster created his Facebook account, he relied solely on his gmail account. His gmail account is effectively his Facewbook ID. Thus, his gmail account definitely proves his Facebook account ownership. Faye at info+rzcifs@support.facebook.com communicated with Lupangster using lupangster's gmail account, but Faye says she 無法核實帳號的擁有權. What else can Faye use to confirm lupangster@gmail.com owns lupangster@facebook.com?

Be reminded that Lupangster started communicating with Faye at info+rzcifs@support.facebook.com because his Facebook account was disabled. Nothing Faye at info+rzcifs@support.facebook.com
wrote addressed this issue. She did not offer an explanation why the account was disabled, or what she intended to do if she could be satisfied.

To summarize: Lupangster has only one email account, his gmail account. He used this gmail account to create a Facebook account, so his gmail account is his Facebook account ID. Facebook disabled his account without telling him why. After Lupangster complained, Faye at info+rzcifs@support.facebook.com started asking Lupangster to prove his identity and communicated with Lupangstger using Lupangster's gmail address. Faye even asked Lupangster for copy of his ID card. Why not ask Lupangster for his driving records, drinking habit, medical records or college transcript? And how would any of these things prove or disprove that lupangster@gmail.com owns lupangster@facebook.com?